Number of paths from (0,1) to (n,0), with vertices (i,k) satisfying 0 <= k <= 3, consisting of segments given by the vectors (1,1), (1,2), (1,-1).

A247354

Number of paths from (0,1) to (n,0), with vertices (i,k) satisfying 0 <= k <= 3, consisting of segments given by the vectors (1,1), (1,2), (1,-1).

Terms

    a(0) =0a(1) =1a(2) =0a(3) =2a(4) =2a(5) =5a(6) =10a(7) =17a(8) =38a(9) =66a(10) =138a(11) =257a(12) =508a(13) =981a(14) =1900a(15) =3702a(16) =7154a(17) =13925a(18) =26966a(19) =52381a(20) =101594a(21) =197150a(22) =382578a(23) =742257a(24) =1440440a(25) =2794777a(26) =5423256a(27) =10522954a(28) =20418882a(29) =39620597

External references